When a fluorescent lamp is energized, the hydrargyrum (mercury) vapor contained in the tube will be stimulated, giving out ultraviolet radiation. When the ultraviolet radiation strikes a phosphor coating lining the interior of the tube, visible light is produced. In order to obtain a certain brightness level of the visible light, the tube shall have a corresponding power rating, which is typically a function of the length of the tube.
The most commonly used tubes are of the straight type; either U-shaped, double U-shaped, or triple U-shaped.
At present, compact fluorescent lamps, such as the uni-spiral or dual spiral tube, are widely used because of their relatively small volume and energy saving characteristic. However, the two end portions of such kind spiral tubes, joining at the base of the fluorescent lamp are all vertical with respect to the base, which is electrically connected to a lamp socket. Such fluorescent lamps cannot be easily manufactured with having a condensed form factor that is commensurate with maintaining a small volume. Lamps made with having smaller volumes are more convenient for the users to handle.
The following prior art discloses the various aspects in the design of a reduced form factor, dual spiral fluorescent lamp and related prior art.
U.S. Pat. No. 5,256,935, granted Oct. 26, 1993, to Y. Dobashi et al., discloses a cold cathode mercury vapor discharge lamp that includes a bulb, a support wire within the bulb, and a cathode electrode having a pair of V-shaped electrode portions mounted in spaced, end to end relationship along the support wire. The electrodes include exterior surfaces facing towards the bulb walls, and interior surfaces facing towards the support wire. Getters are mounted on the exterior surfaces, and mercury discharge units are mounted on the interior surfaces. The two electrode portions are non-overlapping along the support wire.
A compact fluorescent lamp having an even smaller volume, entitled, “Dual Amalgam Dual Spiral Fluorescent Lamp” is disclosed in Chinese Patent Number ZL02215188.5. This fluorescent lamp does not have the two end portions and two electric pins. It is attached directly to a seat extending out from the tube, making the volume much smaller. However, the manufacture of such a fluorescent lamp having such a structure involves a complicated assembly process involving precise workmanship and can only be manufactured after the current machines are modified and adapted correspondingly, thereby increasing the manufacturing cost.
What is needed is a dual spiral compact fluorescent lamp having a condensed form factor and reduced volume for ease and comfort and handling and for simplicity of manufacture using no specialized tooling, while maintaining the same wattage rating and giving the corresponding brightness level. In this regard, the present invention fulfils this need.
It is therefore an object of the present invention to provide for a dual spiral fluorescent lamp having two end portions that are much shortened, thereby having a smaller contained volume than a conventional dual spiral lamp.
It is another object of the present invention to provide for a dual spiral fluorescent lamp having a more compact structure and form factor than a conventional dual spiral lamp.
It is a final object of the present invention to provide for a dual spiral fluorescent lamp that can to be easily manufactured using a conventional producing machine, without the need for re-tooling, thereby lowering the cost of manufacture.